Figure 2.

 Exploring hypotheses of the spread of antiviral‐resistant influenza virus using a mathematical model. (A) We ran simulations to estimate what fractions of influenza cases around the world needed to take oseltamivir to drive the spread of resistance as quickly as was observed for seasonal H1N1, assuming that the resistant strain was exactly as transmissible as the sensitive strain among untreated individuals. The Xs show the observed proportion of circulating seasonal H1N1 strains that were resistant according to surveillance data. The other points represent the median values from 500 simulation runs, and the gray shaded areas cover the outcomes of 95% of the runs. We estimate that <3% of influenza cases around the world used oseltamivir. (B) We simulated the spread of a resistant strain of influenza that is 1% less transmissible, exactly as transmissible, or 1·7% more transmissible than the sensitive strain, and compared the results to the observed prevalence of resistant seasonal H1N1.